Allergy is a serious medical condition affecting millions of people worldwide, with about 15 million people in the United States, including many children. During an allergic reaction, the immune system mistakenly targets an allergen as a threat and attacks it. The allergic reaction may affect the skin, the digestive system, the gastrointestinal tract, the respiratory system, the circulatory system and the cardiovascular system; and in some allergic reactions, multiple organ systems are affected. Allergic reactions range from mild to severe or life-threatening. Severe symptoms may include difficulty in breathing, low blood pressure, chest pain, loss of consciousness, and anaphylaxis. Food allergies are a major health issue in all industrialized countries. People having food allergies currently manage their allergies by avoiding any food that might contain that specific allergen. These restrictions have a major impact on the patients' quality of life and there remains no method for assessing the true allergen content of food. In the United States, food allergy symptoms send someone to the emergency room every three minutes.
Allergen detection is important for many reasons. A fast and accurate detection method and a portable device that can be easily operated by a person with food allergies to test their food and determine accurately and immediately the allergen content will be beneficial to provide for an informed decision on whether to consume or not. In food industry, allergen detection is critical to ensure accuracy of food labeling and to clean contaminants effectively during food production.
Currently available methods for detecting allergens mostly use antibodies based immunochemical methods (e.g., ELISA, lateral flow devices), peptides (e.g., mass spectrometry), enzymes, DNA based methods (e.g., PCR) and other generic/non-specific methods (e.g., visual inspection, ATP tests). These methodologies sometime are very complex, expensive, time consuming and unreliable. A fast and accurate method for determining the absence/presence of an allergen would be of great benefit. Ultrasensitive detection molecules that can detect a trace of an allergen(s) would be essential for developing a sensitive detection method.
Aptamers, which are single stranded (ss) DNA and RNA molecules, can bind to their targets due to their specific three dimensional structures; they offer specific properties which favor them as new detection molecules for protein recognition including allergens. Aptamers and aptamer-based assays have been shown, among many other useful applications (e.g., diagnostic tests) as a promising alternative in food safety control. A recent review describes analytical strategies developed using aptamers for the control of pathogens, allergens, adulterants, toxins and other forbidden contaminants to ensure food safety (Amaya-Gonzalez, et al., Aptamer-Based Analysis: A Promising Alternative for Food Safety Control, Sensors, 2013, 13:16292-16311; and Amaya-Gonzalez, et al., Aptamer binding to coelic disease-triggering hydrophobic proteins: Towards a sensitive gluten detection system. Anal. Chem. 2014, 86(5), 2733-2739). A method of detection of gluten is also described in PCT Publication PCT/ES2013/000133, 28 Jun. 2013, to Amaya-Gonzalez, et al. Other examples include PCT application publication NOs.: WO2013064818 and WO2012081908 (aptamers that specifically bind Staphylococcus aureus); WO2012081906 (aptamers for ompc protein in salmonella tiphimirium strain); WO2009070749 (aptamers for detecting salmonella contamination); and U.S. Pat. Nos. 7,645,582 and 7,838,242 (aptamers that bind to listeria surface proteins) (each of which is incorporated herein by reference in its entirety.)
The present invention provides new aptamer based signaling polynucleotides, compositions comprising such SPNs, and fast, sensitive and accurate assays to detect the absence or presence of allergens, and/or to quantitatively measure the amount of allergen in test samples. The signaling polynucleotides and detection assays developed in the present disclosure may be used in any allergen detection devices in the art, such as microfluidic chips taught in U.S. Pat. No. 8,617,903 and portable devices taught in the commonly owned PCT patent application NO.: PCT/US14/62656 filed on Oct. 28, 2014, and U.S. provisional application No. 62/133,632 filed on Mar. 16, 2015 (each of which is incorporated herein by reference in its entirety).